Paper machine forming section



Nov. 1, 1960 1.. HORNBOSTEL PAPER MACHINE FORMING SECTION Filed Sept.26, 1956 L h2g0 Hambos/e/ 121 75 2,958,379 Patented Nov. 1, 1960 Fire2,958,379 PAPER MACHINE FORMING SECTION Lloyd Hornbostel, Beloit, Wis.,assignor to Beloit Iron Works, Beloit, Wis., a corporation of WisconsinFiled Sept. 26, 1956, Ser. No. 612,182

7 Claims. (Cl. 162-318) This invention relates to a paper formingmachine, and more particularly, to an improved forming section for papermachines.

In one type of paper machine wherein the instant invention isparticularly useful, the forming region of the machine comprises alooped forming wire with a rotatably mounted foraminous cylinder withinthe loop of the forming wire for effecting fibrous web formation on thewire. An inlet feeds stock onto the wire usually along the region of theupper quadrant of the uprunning side of the cylinder. This arrangementis used in cylinder type paper machines wherein a short looped formingWire is trained over the cylinder mold; and this arrangement may also beused in a Fourdrinier type paper machine wherein the Fourdrinier wire istrained around an open breast roll. In either arrangement guide rollswithin the loop of the wire are arranged so that the wire coversapproximately the upper quadrant of the uprunning or oncoming side ofthe rotating cylinder. Sealing means are associated with the wire justbefore it comes in contact with the oncoming (or uprunning) side ofthecylinder and just after the wire is taken away from the off-running sideof the cylinder. Suction applying means cooperate with such sealingmeans to create a suction in the interior of the cylinder mold and itsenclosure and a pressure differential across the upper quadrant on theuprunning side, so as to assist in drawing water from the stock throughthe forming wire and the open face of the cylinder. At higher operatingspeeds, however, it has been found that the paper machines of the typejust described seem unable to effect satisfactory dewatering of the web.The instant invention is based in part on the discovery of the cause ofsuch inadequate dewatering at high speeds and in part upon the discoveryof a method and means for preventing the same. It has been discoveredthat the rotating foraminous cylinders at high operating speeds rotateso rapidly in the operation of the paper machine that centrifugal forceshold the water against the interior of the cylinder along the uprunningand top sides of the cylinder in spite of suction forces applied to thewire. In fact, a layer of Water is actually retained against the insideof the cylinder and the back side of the wire along the upper quadrantof the cylinder on the uprunning side thereof. Such layer of water tendsto be thrown back against the wire (and even back into the web on theopposite side thereof) as the wire is taken away from the off-runningside of the cylinder, and as it passes over the sealing means ordinarilycooperating with the bottom of the wire in this portion of the wire run.

In the instant invention sealing means associated with the bottom sideof the wire at the off-running side of the cylinder in the mannerhereinbefore employed are not used. Instead, a sealing member(cooperating with the suction applying means) is mounted in closerunning relation with the cylinder itself at the off-running sidethereof and spaced from the bottom of the wire. Such sealing means arespaced from the bottom of the wire a predetermined distance to permitthe entry of gas under pressure from a suitable source at higherpressure between such sealing means and the wire, and against thecylinder. This arrangement permits a rush of air back against theforaminous surface of the cylinder just after thewire is separatedtherefrom at the off-running side; and this rush of air drives water(against the centrifugal force) back through the foraminous cylindersurface and breaks up the layer of water tending to be retained on theinside surface of the cylinder. It also permits a pickup roll or suctionpickup roll to take the Web up off a wire free from water on the bottomside.

It is, therefore, an important object of the instant invention toprovide an improved paper machine particularly suited for high speedoperation.

Other and further objects, features and advantages of the presentinvention will become apparent to those skilled in the art from thefollowing detailed disclosure thereof and the drawings attached heretoand made a part hereof.

Figure l is an elevational view of a cylinder type paper machineembodying the instant invention with parts shown in section and partsshown diagrammatically.

Referring now to Figure l, a cylinder type paper ma chine embodying theinstant invention is indicated generally by the reference numeral 200(wherein similar elements to those hereinbefore described have the samereference numerals in the 200 series) and this machine 200 comprises alooped forming wire 211, a cylinder mold 212 within the loop of theforming Wire 211 for effecting fibrous web formation on the wire 211 inthe region 212a of approximately the upper quadrant of the uprunningside (indicated by an arrow) of the cylinder mold 212, and a guide roll213 within the loop of the Wire 211 guiding a reach 211a thereof awayfrom the cylinder mold 212 at the oif-running side of the cylinder mold212 (actually near the top of the off-running side of the cylinder mold212), and an inlet 214 feeding stock onto the oncoming side of the wirecovered cylinder mold 212.

As will be seen, the wire 21'1 passes (in the direction indicated by thearrow heads) along the horizontal reach 211a from the off-running sideof the cylinder mold 212 over a guide roll 213, then down around a lowerguide roll 215 and back beneath a forward guide roll 216 which guidesthe Wire along an upwardly directed reach 21112 past vacuum sealingmeans indicated diagrammatically at 217 onto the upper quadrant 212a ofthe uprunning side of the cylinder mold 212. Stock flows through aninlet 214 onto the wire in the region of said upper quadrant 212a. Inthe region of the quadrant 212a, the wire and the cylinder moldsurfaceare both foraminous cylindrical forming surfaces, which aresuperimposed. Both the foraminous wire surface and the foraminoussurface of the open cylinder mold 212 permit Water to pass throughfreely, so that a fibrous Web W" may form in the region of the quadrant212a.

A pickup felt F (which is actually a looped felt that'may pick up websfrom a plurality of cylinder mold units such as the one here shown) ispositioned above the cylinder mold 12 and the oif-running reach 211a ofthe forming wire 211 to receive the fibrous web W" from the wire 211. Asuction roll 218 with a suction area 218a for web pickup and Webretention on the bottom of the felt F" urges the felt F downwardlyagainst the wire 211- just after the wire 211 separates from thecylinder 212 to assist in web pickup by the felt F", As here shown, thesuction roll 218 and the cylinder mold 212 are in nip-definingrelationship at a nip N just after which the transfer of the Web W" fromthe wire 211 to the felt F" is accomplished; At this nip N the wire 211separates from the off-running side of the cylinder mold 212.

As will be noted, the cylinder mold 212 is rotatably mounted on means(not shown) within a suction or vacuum box indicated generally by thereference numeral 219 which comprises a floor 219a, a forward wall 21%extending upwardy from the floor to the wire seal 217, and a rear wall2190 which, in the prior art, extended upwardly to make wire sealcontact with the bottom of the off-running wire reach 211a. Also,suitable means for evacuating the box 219, such as a pump 220 sh wndiagrammatically are provided, so that a pressure differential may bemaintained across the wire 211 and the cylinder mold surface in theregion of the quadrant 212a to assist in drawing water from the stockand into the interior of the cylinder mold 212.

In the instant invention. the rear wall 2190 of the suction box 219extends upwardly but is spaced from the bottom of the wire reach 211aand is provided at its upper end with a sealing member 219d (which is inthe present embodiment a continuation of the metal wal s of the box 219)that extends back toward the upper portion of the off-runnin s de of thecvh'nder mold 212 to close runn ng relation therewith. The member 219dthus functions as a se l ng member with the surface of the cylinder mold212 in tead of the bottom of the wire 211. Airblast means 221 are inerposed between the wire reach 211a and the sealing member 2 9d forurging a as such as air under p essure back between the wire 211 and thesealing member 2 9d a ainst the surface of the c nder mo d 212. As he eshown. the airblast means 221 compr se a header 2211.1 and a nozzlemember 22% which extends a sub tantial distance into the space betweenthe wire 211 and the sealin member 219a' and is aimed so as to directair at t e off-running side of the nip N". In this wav the a r-blastserves to drive water away at the critica point a d actually the air maybe driven back through the su face of the cylinder mold 212 so as tocomp etel disrupt the layer L of water tend ng to follow the insidesurface of the cylinder mo d 212. in the manner shown in the drawing. Inaddition. the air-blast tends to assist the suction gland 218a of thesuction roll 218 in ccomplishing transfer of the web W" from the wire211 to t e felt F". As here shown diagrammatically a pump 2210 or othersuitable means for producing as under pressure is connected to theheader 221a. The air-blast is concentrated in such a re atively s all reion of the overall surface of the cylinder mold 212 that the amount ofair passing into the c nder at this point is relatively small so thatvacuum within the cylinder mold is not lost.

It will be understood that mod fications and variations may be effectedwithout departing from the spirit and scope of the novel concepts of thepresent invention.

I claim as my invention:

1. In a cylinder type paper machine. in combination, a looped formingwire. a c linder mold within the loop of said forming wire for effe t ngfibrous web formation on the wire, a guide ro l within the loop of saidWire guidin a reach thereof away from the cylinder mold at theoff-running side thereof. a sealin member in close running relation tothe off-running side of said cylinder mold and spaced from said wire.suction means cooperatin with said sealing member to create suctionwithin the cylinder mold. and as-blast means interposed between the wireand sealing member urgin gas under pressure back between the wire andthe sealing member against the c linder mold.

2. In a cylinder type paper machine, in combination, a looped formingwire, a cylinder mold within the loop of said forming wire for effectingfibrous web formation on the wire, an inlet feeding stock onto theoncoming side of the wire covered cylinder mold, a guide roll within theloop of said wire guiding a reach thereof away from the cylinder mold atthe off-running side thereof, a sealing member in close running relationto the off-running side of said cylinder mold and spaced from said wire,suction means cooperating with said sealing member to create suctionwithin the cylinder mold, and gas-blast means interposed between thewire and the sealing member urging gas under pressure back between thewire and the sealing member against the cylinder mold.

3. In a cylinder type paper machine, in combination, a looped formingwire, a cylinder mold within the loop of said forming wire for effectingfibrous web formation on the wire, a guide roll within the loop of saidwire guiding a reach thereof away from the cylinder mold at theoff-running side thereof, -a pickup felt having a felt run positionedabove the reach of said forming wire to receive the fibrous webtherefrom, a sealing member in close running relation to the off-runningside of said cylinder mold and spaced from said wire, suction meanscooperating with said sealing member to create suction within thecylinder mold, and gas-blast means interposed between the wire and thesealing member urging gas under pressure back between the wire and thesealing member against the cylinder mold.

4. In a cylinder type paper machine, in combination, a looped formingwire, a cylinder mold within the loop of said forming wire for effectingfibrous Web formation on the wire, a guide roll within the loop of saidwire guiding a reach thereof away from the cylinder mold at theoff-running side thereof, a pickup felt having a felt run positionedabove the reach of said forming wire to receive the fibrous webtherefrom, a suction roll urging said felt run against said wire reachto assist in web pickup by the felt, a sealing member beneath saidsuction roll in close running relation to the off-running side of saidcylinder mold and spaced from said wire, suction means cooperating withsaid sealing member to create suction within the cylinder mold, andgas-blast means interposed between the wire and the sealing-memberurging gas under pressure back between the wire and the sealing memberagainst the cylinder mold.

5. In a cylinder type paper machine, in combination, a looped formingwire, a cylinder mold 'within the loop of said forming wire foreffecting fibrous web formation on the wire, an inlet feeding stock ontothe oncoming side of the wire covered cylinder mold, a guide roll withinthe loop of said wire guiding a reach thereof away from the cylindermold at the off-running side thereof, a pickup felt having a felt runpositioned above the reach of said forming wire to receive the fibrousweb therefrom, a sealing member in close running relation to theoff-running side of said cylinder mold and spaced from said wire,suction means cooperating with said sealing member to create suctionwithin the cylinder mold, and gas-blast means interposed between theWire and the sealing member urging gas under pressure back between thewire and the sealing member against the cylinder mold.

6. In a cylinder type paper machine, in combination, a looped formingWire, a cylinder mold within the loop of said forming wire for effectingfibrous web formation on the wire, an inlet feeding stock onto theoncoming side of the wire covered cylinder mold, a guide roll within theloop of said wire guiding a reach thereof away from the cylinder mold atthe off-running side thereof, a pickup felt having a felt run positionedabove the reach of said forming wire to receive the fibrous webtherefrom, a suction roll urging said felt run against said wire reachto assist in web pickup by the felt, a sealing member beneath saidsuction roll in close running relation to the off-running side of saidcylinder mold and spaced from said wire, suction means cooperating withsaid sealing member to create suction within the cylinder mold, andgas-blast means interposed between the wire and the sealing memberurging gas under pressure back between the wire and the sealing memberagainst the cylinder mold. p

7. In a paper machine, in combination, a looped forming wire, arotatably mounted foraminous cylinder within the loop of said formingwire for effecting fibrous 2,958,379 5 web formation on the wire, guidemeans within the loop References Cited in the file of this patent ofsaid wire guiding a reach thereof away from said cylinder at theoff-running side thereof, a sealing mem- UNITED STATES PATENTS her inclose running relation to the off-running side of ,262,698 Pope Apr. 16,1918 said cylinder and spaced from said wire, suction means 5 ,534,620Wagner Apr. 21, 1925 cooperating with said sealing member to createsuction 1,581,656 Monaghan Apr. 20, 1926 within said cylinder, andgas-blast means interposed be- 2, 54,719 Berry Apr. 18, 1939 tween thewire and the sealing member urging gas under 2,162,097 Metcalf June 13,1939 pressure back between the wire and the sealing member 2,535,732Goodwillie Dec. 26, 1950 against said cylinder. 1 2,755,710 BeachlerJuly 24, 1956

